Citations

Abstract Background Leptomeningeal disease (LMD) remains a challenging complication of both solid tumors and hematologic malignancies, with diagnosis traditionally relying on cerebrospinal fluid (CSF) cytology, which has limited sensitivity. Circulating tumor DNA (ctDNA) analysis in CSF has emerged as a promising diagnostic and molecular profiling tool that may improve detection and guide treatment decisions. We will report real-world clinical experience using a CSF ctDNA assay (Menarini Silicon Biosystems) in routine neuro-oncology practice. Methods Retrospective analysis of over 100 CSF specimens obtained from patients with suspected or confirmed LMD will be conducted. Clinical data to be collected: patient demographics, tumor histology, indication for testing, and prior treatments. ctDNA assay results will be compared with conventional CSF cytology. Molecular alterations identified through ctDNA testing will be recorded, along with subsequent treatment decisions, including use of targeted therapies, systemic therapy modifications, radiation therapy, or intrathecal approaches. Preliminary clinical outcomes, including radiographic response, progression patterns, and survival trends, will be explored. Descriptive statistical methods will be used to summarize the findings. Results We anticipate that among analyzed specimens, ctDNA testing will provide clinically meaningful diagnostic yield across multiple tumor histologies. Concordance and discordance patterns between ctDNA results and conventional cytology will be evaluated, including cases in which ctDNA identified molecular alterations despite negative cytology. Actionable genomic findings in a subset of patients will be analyzed and presented. Early outcome observations that ctDNA-informed management may facilitate more personalized care will be reported. Conclusions CSF ctDNA analysis represents a feasible and informative adjunct to conventional cytology in the evaluation of patients with suspected LMD in real-world clinical practice. Beyond diagnostic support, molecular profiling from ctDNA may influence treatment selection and enable precision oncology approaches in this high-risk population. Prospective studies are warranted to define sensitivity, specificity, and the impact of ctDNA-guided interventions on clinical outcomes.

Abstract BACKGROUND Treatment of high-grade glioma (HGG) remains a challenge. Several groups have developed ex vivo drug sensitivity assays to evaluate susceptibility of the tumor tissue to specific chemotherapeutics. This tool, in addition to molecular analysis of tumors might provide another layer of confidence in choosing treatments for patients with high-grade gliomas. METHODS 3D PredictTM platform (Kiyatec, Greenville, SC, USA) was tested at three academic medical centers in the United States. Twelve patients with newly diagnosed and recurrent HGGs were included. Tumor spheroids created ex vivo were exposed to twelve pre-selected drugs. Responses were reported as: no response, moderate response and response. We analyzed: demographics, histopathology, stage of disease, success rate and results of the ex vivo assay and clinical implications. RESULTS Majority of patients were women (67%). Median age was 58.5. Histology: GBM-83%, HGGs-17%. Eighty three percent of the samples represented recurrent disease. Sixty percent represented first recurrence while the remaining 40% represented 2nd or 3rd recurrence. Eight out of 12 tissue samples (67%) were successfully tested ex vivo. In six cases (75%), the information was used for immediate clinical decision making. In 2 cases, the decision was deferred until the next progression of the disease. The drugs chosen for treatment based on assay results included: olaparib (the assay was positive for response to rucaparib), temozolomide, lomustine, carboplatin and irinotecan. CONCLUSIONS This platform is easy to use in a standard clinical setting, the success rate for creating viable spheroids for drug sensitivity testing is high and the information obtained can be useful in clinical practice. Addition of other agents to the assay, correlation with molecular testing of the tumor tissue and attempt to assess response to drug combinations should be considered in further development of this technology. Prospective clinical trial is needed to validate this approach for routine clinical use.

Abstract BACKGROUND In May 2022 the Food and Drug Administration approved fam-trastuzumab deruxtecan-nxki (FAM-TRAS) for adult patients with unresectable or metastatic Her-2 positive breast cancer who have received prior Her-2-based regimen and developed recurrence withing 6 months of completing therapy. Efficacy of the drug was established in the DESTINY-BreastO3 study. It has been suggested that fam-trastuzumab deruxtecan crosses blood-brain barrier, similarly to trastuzumab and another drug conjugate trastuzumab-DM1. CNS responses in patients with Her2 positive metastatic breast cancer have been reported. ERBB2 is a receptor tyrosine kinase from the family of EGFR/ERBB/HER family of kinases and its alterations can serve as a biomarker and actionable target in solid tumors. Here we present a case of CNS metastases from ERBB2 positive lung adenocarcinoma treated successfully with FAM-TRAS alone. METHODS Case report. RESULTS 50 y old man presented with a persistent cough. CT chest showed RUL nodule and peribronchial lymphadenopathy. Biopsy was positive for adenocarcinoma. Molecular testing has shown ERBB2 exon20 insertion, TP53 pathogenic variant, PDL1 positive (1%), and BRACA1 mutation. The patient had a solitary brain metastasis at the time of the initial diagnosis. He was started on FAM-TRAS and CNS response was seen while lung disease progressed. He was switched to immunotherapy but developed pneumonitis and therapy was stopped. He subsequently developed innumerable brain metastases and was restarted on FAM-TRAS. After 2 doses, dramatic response in CNS was seen with lung disease was stable. CONCLUSIONS This case demonstrates the critical importance of molecular testing in neuro-oncology in the era of novel systemic therapies, many with good blood-brain barrier penetration. Systemic therapies for brain metastases can be successfully implemented in the right clinical setting and they can allow for the deferral of radiotherapy. ERBB2 mutations can guide clinicians when choosing therapy for many solid tumors, including those with brain metastases.